If you checked the birth dates of her calves you'd see most had different birth dates. They just didn't follow the naming convention of adding 'ET' to the names.
Slightly off-topic, wouldn't you love to have direct access to the Hereford database and run the queries as you want, not the generic ones they allow? Think about it, you could find animals which were the products of half-sibling matings, what percentage of the daughters of a bull/cow actually went on to produce multiple calves...
Btw, all our heifers which were twins to bulls have been Free Martins. We kept one which passed the physical exam, cycled, but never conceived. She was delicious.
I did not pull a calf list. However, I noticed in the pdf download she had 30 calves listed for BW ratio. Usually, I don't see the restricted ET calves listed there but further down in the carcass ratios. If what you are saying is correct, then this is an error unless I am mistaken in my reasoning.
I am considering negotiating with the AHA either with a business proposition or through a research proposition in order to access the database. It would be difficult for me to locate hidden patterns without this hidden data. I am pretty sure there is at least one software product that can access it so I don;t see why another corporation couldn't. If we could just locate all the cow line with tripletts, we could probably retire 10 years earlier. I believe this trait alternates generations like in my ex-wife's family. Would it be possible to flush these resultant cows to generate three times the number of embryos?